Steven Spielberg and George Lucas bemoaning the commercialised state of modern Hollywood is a bit like Amazon complaining about the decline of old-fashioned bookshops. Last week, speaking at the University of Southern California, the two film-makers outlined a doomsday scenario of hugely inflated ticket prices, limited choice at the box office and no place for talented, visionary directors – like themselves. Spielberg only just got his Oscar-winning Lincoln into cinemas, he revealed, otherwise it would have gone straight to television. Likewise, George Lucas struggled to get his Red Tails movie seen. Were just a handful of big budget tent-pole Hollywood movies to flop, the two men warned, there could be an industry-changing "implosion – or a big meltdown".

The instinctive response to this apocalyptic prophecy is, "Bring it on." The second is, "Hang on, you're Steven Spielberg and George Lucas." We'll get to the second point later, but the subtext of what these two Hollywood titans were saying is, like national banks, blockbuster movies are simply too big to fail. They're so expensive, and there's so much riding on them, they have to be supported, regardless of whether or not they're actually any good. This has been true for some time. I've no argument with blockbuster movies per se. The good ones deserve every penny they get.

The trouble is, the bad ones seem to get those pennies too. Remember Green Lantern? I don't blame you if you don't, but it was a lame comic-book movie that came out two years ago. It was roundly trashed by the critics (a Rotten Tomatoes score of 26%) and yet it still turned a profit. Likewise, top spot at last week's box office in the UK (and about 20 other countries) was After Earth, the Will Smith sci-fi that earned one-star reviews across the board and a Rotten Tomatoes score of 11%. Even the worst movies somehow end up making money.

Just as we're propping up our flatlining economy via quantitative easing and manipulated interest rates, so the film industry now has an artillery of techniques to ensure big movies don't fail. Take product placement. It's been around for decades, but it reached surreal extremes last week when it was revealed that the Superman reboot, Man Of Steel, had already recouped $170m (£108m) before it was even released – three-quarters of the movie's budget. This was thanks to a record 100 "global promotional partners", including Gillette, Lego, Walmart, Converse, Carl's Jr burgers and Hershey's Twizzlers. Even the US National Guard has chipped in with its "Soldier of Steel" recruitment campaign. Clearly, we're headed for some dystopian sci-fi future where blockbusters will make a profit even if nobody goes to see them at all.

But see them we will, in droves, of course. Well-timed marketing strategies now ensure that awareness and media buzz are at a maximum, and critical and public opinion at a minimum, at the precise moment a movie swamps cinema screens across the world, ensuring a big sugar-rush in the first week of release. These techniques are distorting the form and content of our movies, as well as the basic competitive mechanism that's supposedly underpinning the industry. Without them, more movies would be failing already. Is the bubble about to burst? Lucas and Spielberg seem to think so. Others hope so. What could be healthier for the cinema ecosystem than a good old mass extinction? A disaster to end all disaster movies?

As for Lucas and Spielberg themselves, If there's something wrong with the age of commercialised film-making it's difficult to think of two film-makers more culpable. Yes, they've made some great movies, but they also double-handedly ushered in the age of the blockbuster they now bemoan. They have had a hand in eight of the top 20 highest grossing movies of all time, inflation-adjusted.

Lucas might have virtually started a new religion with the Star Wars movies, but he milked them for every merchandising dollar he could for 35 years, then sold the rights to Disney for a staggering $4bn. How does he expect Disney to recoup that money? By making low-budget Star Wars art movies? To then turn around and suggest that, "I couldn't even get Red Tails into theatres and I'm George Lucas" is even more hypocritical. As if the Lucas name alone should suffice, rather than the quality of the movie, which, in this case, was not high.

And yes, Spielberg, you gave us Lincoln, Schindler's List, Saving Private Ryan and many more decent movies. But you also gave us crud like Indiana Jones and the Kingdom of the Crystal Skull. You produced all the Transformers movies. The list goes on. Without all those bludgeoning, competition-crushing commercial movies to his name, Spielberg wouldn't have the clout to make his award-winning prestige movies.

Spielberg and Lucas rose to prominence on the coat tails of the last great movie-industry "implosion": the New Hollywood movement of the 1970s. It's now remembered as a golden age of distinctive directors and personal, creative, edgy, grown-up, enduring movies – many of them made by Spielberg and Lucas's buddies like Martin Scorsese, Francis Ford Coppola, Robert Altman and William Friedkin. The reason that golden age came to an end is largely because movies like Jaws and Star Wars hogged the screens and raked in all the cash, just as the likes of Man Of Steel and After Earth do today. So bring on the meltdown! Without these fiscally stimulated, steroid-pumped blockbusters, perhaps there'd be room for a new, New Hollywood to grow – at least until the new Spielbergs and Lucases came to mess it all up again.